Process for imparting transparent effects to cotton



Patented Sept. 26, 1922.

HEINRICH FOBSTER, F BRUGGEN, SWITZERLAND, ASSIGNOR 0F ONE-HALF To CONRAD FORSTER, OF DEDHAM, MASSACHUSETTS. I

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No Drawing.

To all whom it may concern:

Be it known that I, HEINRICH FoRs'rnR, a citizen of the Swiss Republic, residing at Bruggen, Ganton St. Gallen, Switzerland, have invented certain new and useful Imrovements in Processes for Imparting Transparent Effects to Cotton; and I do hereby declare the following to be a full, clear, and exact description of the invention,

such as will enable" others skilled in the art to which itappertains to make and use the same. a

This invention relates to a process for im parting transparent effects to cotton.

The object of the invention is to provide a novel process by which superior transparent effects may be imparted to cotton, cotton fabrics, and mixed fabrics containing cotton.

It has heretofore been recognized that certain transparent effects may be imparted to fcotton by successive treatments of the cotton with reagents of dilferent types and characteristics, having different actions upon cotton, andof which strong sulphuric acid and;

concentrated soda lye may be taken as examples of each type. To produce such effects the cotton was either treated first with strong sulphuric acid for a few seconds followed by treatment with strong soda lye or,

' on the other hand, the cotton was treated first with. strong soda lye and then with strong sulphuric acid for a few seconds. The concentration of the sulphuric acid was over 50% Baum. It has also been recognized that the transparent efi'ec-ts secured by these processes could be improved to some extent by preceding the initial step in each process with a treatment of the cotton with a reagent of the opposite type from the reagent 40 used in the initial step of the process, that is to say, the first processconsisting of a treatment with sulphuric acid followed by a treatment with soda lyewas improved by preceding the treatment with sulphuric acid by a treatment with-' strong soda lye, and also the process consisting of the treatment with soda lye followed by treatment with strong sulphuric acid, was improved by preceding the soda lye treatment with treatment, with strong sulphuric acid. These two proo other temperature followed by treatment 100 Application filed September 21, 1920. Serial No. 411,849.

esses may be symbolically expressed as follows? able to the successful operation of the subsequent treatments. It is to be noted that the first two treatments in each of processes 1 and 2 are with reagents ofopposed types.

It has heretofore been considered impossible to obtain any reaction or effect upon cot- 66 ton by successive treatments with'reagents of the same general type, that is for example by success ve treatments with reagents having an action upon cotton similar to sulphurlc acld. 70

I have discovered that transparent effects of superior and improved quality may be produced upon cotton by successive treatments with reagents of the same general :ype but under different conditions of opera- .76

The conditions of operation under which the cotton is treated with reagents of one type may be varied in several ways, for example, successive treatments of cotton with acids of different strengths followed by treatment with strong soda lye produced transparent effects upon cotton vastly superior to those produced by any of the processes heretofore known. Different reagents 56 of the same type may be used in each of thesuccessive steps but under different conditlons of operation. Instead of varying the strength of the reagent to be used in a particular treatment, the temperature thereof may be controlled with or without variation in its strength. It has been heretofore recognized that in general the effectiveness of a reagent is in a large measure dependent upon its temperature. It is therefore 05- sible to obtain desirable transparent efiects by treatment with a reagent of one type at one temperature, treatment with the same reagent or a reagent of the same type at anwith a reagent of a different type. The conditions of operation may be varied in other ways.

The invention is preferably embodied in the following process which is described in detail as follows: I

The cottonfabric is dipped in sulphuric acid of a strength corresponding to pure sulphuric acid having a gravity below 505 Baum. The exact strength of this acid may be varied within reasonable limits and is preferably a strength corresponding to sulphuric acid of a gravity of 49 Baum.

The cotton is permitted to remain in this acid bath for a period of approximately two minutes after which it is removed therefrom, washed thoroughly, and dried. The cotton is then dipped into a second sulphuric acid bath for a period of a few seconds, preferably four or five, and the strength of this second bath corresponds to pure sulphuric acid having a gravity above 50% Baum, and preferably 54 Baum. After the cotton has remained in this second acid bath for a period of approximately five seconds, it is removed therefrom and washed, and thereafter mercerized in the usual way in a bath of soda lye of a strength above 15 Baum. This process may be symbolically expressed as follows:

H SO, below 5% B.H SO above 50 B.NaoH.

During the process shrinkage of the ma terial is prevented as much as possible so that the material is in a stretched condition,

The superiority of the transparent efi'ects produced upon the cotton material treated in accordance with the present invention may be readily observed by comparison with fabrics treated according to previous processes. The fabrics treated according to the present invention are far more transparent, more even, and more silk-like.

Among the reagents having an action upon cotton similar to sulphuric acid, and which may be employed in accordance with the present invention are included phosphoric acid, hydrochloric acid, nitric acid or any mixtures thereof including mixtures with sulphuric acid, and also zinc chloride solution and ammoniacal solutions of copper hydrate. All of these reagents may be regarded as parchmentizing reagents.

The cotton material may be treated in any desired manner in accordance with the pres ent process either in whole or in part in order to produce the pattern effects according to the well-known printing process.

In the specification and claims the gravity neoaies of solutions expressed in degrees Baum are to be considered as degrees Baum at a temperature of approximately 15 0.

Having thus described the invention, What is claimed is 1. The process of imparting transparent effects to cotton which consists in subjecting the cotton to treatment with successive parchmentizing reagents under different conditions of operation and thereafter mercerizing the cotton.

2. The process of imparting transparent effects to cotton which consists in subjecting the cotton, while in a stretched condition. to treatment with successive parchmentizing reagents under different conditions of operation and thereafter mercerizing the cotton.

3. The process of imparting transparent effects to cotton which consists in subjecting particular portions of the cotton to treat ment with successive parchment-izing reagents under different conditions of operation and thereafter mercerizing the cotton.

4. The process of imparting transparent efiects to cotton which consists in subjecting the .cotton to treatment with successive parchmentizing reagents of difierent strengths, and thereafter mercerizing the cotton.

5. The process of imparting transparent effects to cotton which consists in subjecting the cotton to treatment with successive parchmentizing reagents of different and increasing strengths, and thereafter mercerizing the cotton.

6. The process of imparting transparent efi'ects to cotton which consists in subjecting the cotton to treatment first with sulphuric acid below 50% Baum, then with sulphuric acid above 50:? Baum and then with concentrated caustic alkali.

7. The process of imparting transparent effects to cotton which consists in subjecting the cotton to treatment for a period of substantially two minuteswith sulphuric acid having a gravity between 4550 Baum, washing and drying the cotton, then subjecting the cotton to treatment for a few seconds with sulphuric acid having a gravity above 5011* Baum, washing and there after mercerizing the cotton in concentrated soda lye.

8. The process of imparting transparent effects to cotton which consists in subjecting the cotton to successive parchmentizing and mercerizing treatments, one of such treatments being carried out in two successive steps under different conditions of operation.

HEINRICH FORSTER. 

